Composite pile foundation giving consideration to overall stability and differential settlement reduction

Abstract

A composite pile foundation giving consideration to overall stability and differential settlement reduction comprises a seawall body, the seawall body is provided with two rows of cast-in-situ bored piles, the front row of the seawall body near the sea is a close-packed cast-in-situ pile wall, the two rows of cast-in-situ bored piles penetrate through a deep sliding arc, and a soil body reinforcing area on the seawall body near the shore is internally provided with a plurality of cast-in-situ bored piles. A plurality of cement mixing piles arranged in a quincunx shape are arranged, and the processing width of the cement mixing piles corresponds to the management range of the inner side of the seawall. The problems that riprap suppression is not allowed in the sea area range in front of the seawall, so that the seawall is overall stable, and after construction, a seawall body and filling soil on the rear side are structurally separated due to sedimentation are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of seawall pile foundations, in particular to a composite pile foundation that takes into account both overall stability and reduced uneven settlement. Background Art

[0002] At present, the commonly used methods for treating the foundation of dikes and ponds are: excavation of soft soil, accelerated drainage by blowing sand or gravel cushion, drainage consolidation by preloading, drainage consolidation by plastic drainage board, vacuum preloading, reinforcement by high-strength geotechnical materials, blasting and squeezing silt, pile foundation, etc. In view of the characteristics of high seawalls, thick soft layers of foundation, and high water content in coastal areas, it is difficult for a single geotextile reinforcement to meet the stability requirements. The cost of vacuum preloading and blasting and squeezing silt is relatively high, and the vacuum preloading treatment method is limited by professional equipment and teams. The explosive construction of blasting and squeezing silt has a greater impact on the surrounding areas of the project area. The drainage consolidation method with plastic drainage board is usually used for earth-rock dike structures, while for seawalls with light structures, the pile foundation treatment method is mainly used.

[0003] The problem with the existing technology is that for the seawalls of coastal development plots, the land behind the seawalls often has the characteristics of being close to the foot of the inner slope of the seawall and having a large load, and the sea area in front of the seawall does not allow stone dumping for suppression. Therefore, it is difficult to solve the overall stability problem by simply using conventional pile foundation treatment methods such as bored cast-in-place piles for foundation treatment of the seawall body. After construction, it will also cause the seawall body and the back fill to become structurally detached due to settlement.

[0004] Moreover, the existing seawall still has the problem of overall sliding due to poor foundation and heavy backloading. The settlement of the existing pile foundation is calculated to be within 5cm, while the settlement of the backfill soil behind the embankment generally reaches more than 70cm.

[0005] Therefore, it is necessary to design a composite pile foundation structure that takes into account both overall stability and reduction of uneven settlement. Utility Model Content

[0006] In order to solve the deficiencies of the above-mentioned technologies, the present utility model provides a composite pile foundation that takes into account both overall stability and the reduction of uneven settlement, and ensures the flow capacity of the river while meeting the landscape needs of tourists. The technical solution of the present utility model: a composite pile foundation that takes into account both overall stability and the reduction of uneven settlement, including a seawall body, the seawall body is provided with two rows of bored cast-in-place piles, wherein the front row on the seaside is a densely packed cast-in-place pile wall, the two rows of bored cast-in-place piles are long enough to penetrate deep sliding arcs, and a plurality of cement mixing piles arranged in a plum blossom shape are provided in the soil reinforcement area on the shore side of the seawall body, and the processing width of the cement mixing piles corresponds to the inner management range of the seawall.

[0007] Using the above technical solution, the deep sliding arc of the seawall refers to the deep sliding damage phenomenon that occurs when the seawall body or foundation is subjected to external forces (such as wave impact, seepage, earthquake, etc.) or internal stress changes. This sliding usually develops along a relatively fixed arc path to form a sliding belt or sliding surface.

[0008] Therefore, the two rows of bored cast-in-place piles of the main body of the seawall should be long enough to penetrate the deep sliding arc to ensure the stability of the main body of the seawall.

[0009] Cement mixing piles are set up in the seawall soil reinforcement area to reinforce the seawall foundation, and the weak soil layers are removed, high-quality soil materials are replaced, and drainage systems are set up to improve the bearing capacity and stability of the foundation. The shear strength and overall stability of the soil are improved.

[0010] The utility model is further configured as follows: the bored cast-in-place piles and densely packed cast-in-place pile walls have a pile spacing of 1.0 m, an inner row pile spacing of 3.0 m, and a pile length exceeding 45 m.

[0011] The utility model is further configured as follows: the soil reinforcement area penetrates the silt layer, the cement mixing piles are 17m long, and the pile spacing is 1.6m.

[0012] With the above technical solution, the silt layer usually has a low bearing capacity and high compressibility, which poses a potential threat to the stability and safety of the seawall. If it is not penetrated, the silt layer may deform or break under external loads or internal stress changes, thus affecting the stability of the entire seawall.

[0013] The penetration of cement mixing piles into the silt layer can effectively connect the reinforced area with the more solid soil layer below, forming an overall more stable structure. This can not only improve the bearing capacity of the seawall, but also reduce the problems of seawall settlement or cracking caused by deformation of the silt layer.

[0014] The utility model is further configured as follows: the main body of the seawall is an L-shaped retaining wall, a cantilevered platform on the top of the seawall and a plurality of pedestals and pillars located vertically below the cantilevered platform on the top of the seawall are arranged on the side of the L-shaped retaining wall facing the sea, and the pedestals are provided with bored cast-in-place piles.

[0015] Beneficial effects of the utility model:

[0016] 1. Enhance the overall stability of the seawall

[0017] The main body of the seawall uses bored cast-in-place pile foundations, the piles penetrate deep sliding arcs, the back fill is treated with cement mixing piles, and the soil reinforcement area penetrates the silt layer, so that the shear strength of the foundation soil in various places is enhanced, thereby solving the overall sliding problem of the seawall in coastal development areas (poor foundation, large back-side loading). Calculated by the Swedish arc method, the overall stability coefficient during the construction period increased by about 100%, and the overall stability coefficient during the operation period increased by about 60%.

[0018] 2. Reduce uneven settlement of the embankment and the backfill

[0019] According to the Code for Design of Building Foundations (GB5007-2002) and the Code for Design and Construction of Sheet Pile Wharfs, the final settlement of the seawall pile foundation is generally calculated using the equivalent action layered summation method. After calculation, the settlement of the pile foundation is within 5 cm, while the settlement of the backfill soil behind the embankment generally reaches more than 70 cm. Through the mixing pile treatment, the settlement of the backfill soil behind the embankment is composed of the deformation of the composite soil layer of the mixing pile and the deformation of the soil layer under the pile end. After calculation, the settlement of the backfill area behind the embankment is about 40 cm, and most of the settlement is completed during the construction period, and only a certain settlement height needs to be reserved. Through the transition treatment of the mixing pile foundation, the settlement of the seawall pile foundation part is coordinated with the settlement of the backfill part, reducing uneven settlement and avoiding structural detachment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The structure of the embodiment of the utility model Figure 1 ;

[0021] Figure 2 It is a schematic diagram of stability analysis of an embodiment of the utility model.

[0022] Among them, 1-the main body of the seawall, 11-the cantilevered platform on the top of the seawall, 12-the pedestal, 13-the pillars, 2-the bored cast-in-place piles, 3-the close-packed cast-in-place pile wall, 4-the soil reinforcement area, 5-the cement mixing piles, and 6-the silt layer.

[0023] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. DETAILED DESCRIPTION

[0024] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be further described in detail in detail and in detail in conjunction with the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0025] As the instruction manual Figure 1-2 As shown, a composite pile foundation that takes into account both overall stability and reduction of uneven settlement includes a seawall body 1, wherein the seawall body 1 is provided with two rows of bored cast-in-place piles 2, wherein the front row on the seaside is a densely packed cast-in-place pile wall 3, the two rows of bored cast-in-place piles 2 have pile lengths that penetrate deep sliding arcs, and a plurality of cement mixing piles 5 arranged in a plum blossom shape are provided in a soil reinforcement area 4 on the shore side of the seawall body 1, and the processing width of the cement mixing piles 5 corresponds to the inner management range of the seawall.

[0026] The deep sliding arc of the seawall refers to the deep sliding damage phenomenon that occurs when the seawall body or foundation is subjected to external forces (such as wave impact, seepage, earthquake, etc.) or internal stress changes. This sliding usually develops along a relatively fixed arc path, forming a sliding belt or sliding surface.

[0027] Therefore, the two rows of bored cast-in-place piles 2 of the seawall body 1 should be long enough to penetrate the deep sliding arc to ensure the stability of the seawall body 1 .

[0028] Cement mixing piles 5 are set in the seawall soil reinforcement area 4 to reinforce the seawall foundation, and the weak soil layer is removed, high-quality soil is replaced, and a drainage system is set up to improve the bearing capacity and stability of the foundation. The shear strength and overall stability of the soil are improved.

[0029] The bored cast-in-place piles and the densely packed cast-in-place pile wall 3 have a pile spacing of 1.0 m, an inner row pile spacing of 3.0 m, and a pile length exceeding 45 m.

[0030] The soil reinforcement area 4 penetrates the silt layer 6, and the cement mixing piles 5 are 11 meters long and are arranged with a pile spacing of 1.6 meters.

[0031] The silt layer 6 usually has a low bearing capacity and high compressibility, which poses a potential threat to the stability and safety of the seawall. If it is not penetrated, the silt layer 6 may deform or break under external loads or internal stress changes, thereby affecting the stability of the entire seawall.

[0032] The cement mixing piles 5 penetrate the silt layer 6 to effectively connect the reinforced area with the lower more solid soil layer to form a more stable structure as a whole. This can not only improve the bearing capacity of the seawall, but also reduce the problems of seawall settlement or cracking caused by deformation of the silt layer 6.

[0033] The main body 1 of the seawall is an L-shaped retaining wall, and a cantilevered platform 11 is arranged on the seaward side of the L-shaped retaining wall, and a plurality of caps 12 and pillars 13 are located vertically below the cantilevered platform 11 . The caps 12 are provided with bored cast-in-place piles 2 .

[0034] 1. Enhance the overall stability of the seawall

[0035] The main body 1 of the seawall is based on bored cast-in-place piles 2, the piles penetrate deep sliding arcs, the back fill is treated with cement mixing piles 5, and the soil reinforcement area 4 penetrates the silt layer 6, so that the shear strength of the foundation soil in various places is enhanced, thereby solving the overall sliding problem of the seawall in coastal development areas (poor foundation, large back load). Calculated by the Swedish arc method, the overall stability coefficient during the construction period increased by about 100%, and the overall stability coefficient during the operation period increased by about 60%.

[0036] 2. Reduce uneven settlement of the embankment and the backfill

[0037] According to the Code for Design of Building Foundations (GB5001-2002) and the Code for Design and Construction of Sheet Pile Wharfs, the final settlement of the seawall pile foundation is generally calculated using the equivalent action layered summation method. After calculation, the settlement of the pile foundation is within 5 cm, while the settlement of the backfill soil behind the embankment generally reaches more than 10 cm. Through the mixing pile treatment, the settlement of the backfill soil behind the embankment is composed of the deformation of the composite soil layer of the mixing pile and the deformation of the soil layer under the pile end. After calculation, the settlement of the backfill area behind the embankment is about 40 cm, and most of the settlement is completed during the construction period, and only a certain settlement height needs to be reserved. Through the transition treatment of the mixing pile foundation, the settlement of the seawall pile foundation part is coordinated with the settlement of the backfill part, reducing uneven settlement and avoiding structural detachment.

[0038] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A composite pile foundation that takes into account both overall stability and reduced uneven settlement, characterized in that: It comprises a seawall body, which is provided with two rows of bored cast-in-place piles, wherein the front row on the sea side is a densely packed cast-in-place pile wall, the two rows of bored cast-in-place piles are long enough to penetrate deep sliding arcs, and a plurality of cement mixing piles arranged in a plum blossom shape are arranged in the soil reinforcement area on the shore side of the seawall body, and the processing width of the cement mixing piles corresponds to the inner management range of the seawall.

2. A composite pile foundation that takes into account both overall stability and reduced uneven settlement according to claim 1, characterized in that: The bored cast-in-place piles and densely packed cast-in-place pile walls have a pile spacing of 1.0m, an inner row pile spacing of 3.0m, and pile lengths exceeding 45m.

3. The composite pile foundation according to claim 1 that takes into account both overall stability and reduction of uneven settlement, characterized in that: The soil reinforcement area penetrates the silt layer, and the cement mixing piles are 17 meters long and are set at a pile spacing of 1.6 meters.

4. A composite pile foundation that takes into account both overall stability and reduced uneven settlement according to any one of claims 1 to 3, characterized in that: The main body of the seawall is an L-shaped retaining wall, and a cantilevered platform on the top of the embankment and a plurality of pedestals and pillars located vertically below the cantilevered platform on the side of the L-shaped retaining wall facing the sea are arranged, and the pedestals are provided with bored cast-in-place piles.

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